Yarrows Yarksis

The Yarrows Yarksis is a tandem-rotor helicopter that was developed and built by Yarrows Helicopter Ltd of Victoria, British Columbia. It was based on the British Bristol Belvedere helicopter that was operated by the Royal BC Air Force from 1961 and the BC Army from 1965.

Bristol Belvedere
The Bristol Belvedere was built in the United Kingdom by the Bristol Aeroplane Company.

The RBCAF took delivery of 18 units in 1961, designated Belvedere HC.1 (serial numbers BC14101 to BC14118). As in British service, they were plagued with problems, and when the BC-built derivative, the Yarksis HC.1, entered service in 1968, all 18 were retired at once.

The BC Army received 9 units in 1962, designated Belvedere AHC.1 (serial numbers AA7-001 to AA7-009). These were also problematic, but delays in developing the Army-specific variant of the Yarksis 1 kept them in service until 1971, making BC Army Aviation the last operator of any Bristol-built Belvedere helicopter.

Specifications

 * Crew: 3
 * Capacity: 19 fully-equipped troops or 22 passengers or cargo or 12 stretchers plus 2 seats plus 1 attendant
 * Length: 54 ft 5 in
 * Empty weight: 11350 lbs
 * MTOW: 19000 lbs
 * Powerplant: 2x Napier Gazelle turboshafts (1465 hp each)
 * Cruise speed: 136 mph
 * Range: 460 mi
 * Service ceiling: 12000 ft

Yarrows Yarksis HC.1, HSR.1, HASR.1, AHC.1
Yarrows Helicopter obtained a licence from Bristol to manufacture the Belvedere and the Sycamore helicopters, and in both cases, Yarrows, with assistance from De Havilland of BC, undertook further developments to the original design before production began.

The first variant produced was the Yarksis HC.1, of which 8 were delivered to the RBCAF (serials BC 14301 to BC 14308) and 4 to the Royal BC Constabulary in 1968 and 6 to the Royal Mail of BC in 1969, and a total of 63 for various civilian operators between 1968 and 1979.

A search-and-rescue variant was developed at the same time as the HC.1, to which they were identical, with the addition of SAR-related equipment. 12 were delivered to the RBCAF, designated Yarksis HSR.1 (serials BC13301 to BC13312), and 10 to the Royal BC Navy, designated Yarksis HASR.1 (serials NH3101 to NH3110) in 1968-1969. A further six were delivered to the British Columbia Coast Guard in 1969, along with twelve more in 1971 to the Philippine Air Force.

A variant was also produced for the BC Army, but some difficulties in implementing some Army-specific features caused the introduction of the type to be delayed until 1971. Twelve were eventually delivered (serials AA9-001 to AA9-012) in that year. A further 17 were built for export, with 3 going to the Jamaican Defence Force in 1971 and 14 to the Royal Rhodesian Air Force in 1971-1972.

Specifications

 * Crew: 3 (4 for SAR versions)
 * Capacity: 19 fully-equipped troops or 22 passengers or cargo or 12 stretchers plus 2 seats plus 1 attendant
 * Length: 54 ft 5 in
 * Empty weight: 13300 lbs
 * MTOW: 24100 lbs
 * Powerplant: 2x Napier Gazelle 501 turboshafts (1650 hp each)
 * Max speed: 160 mph
 * Cruise speed: 145 mph
 * Range: 500 mi
 * Service ceiling: 15000 ft

Yarrows Yarksis HS.1
At the same time that the RBCN placed its initial order with Yarrows in 1966 for the HASR.1, a requirement was issued for a Yarksis-based anti-submarine helicopter. The finalised design was eight feet shorter than the HASR.1, and featured a number of ASW-specific systems not present on other versions. 24 were delivered to the RBCN in 1969-1970 (serials NH6301 to NH6324).

The HS.1 carried a surface-search radar in a ventral radome, a British-made Plessey Type 195 dipping sonar and a dispenser for 30 sonobuoys, along with the necessary onboard computers and other systems. Further, it could carry four torpedoes or four depth charges, or four Nord AS.12 air-to-surface missiles built under licence by Fairey BC.

Specifications

 * Crew: 5
 * Length: 46 ft 5 in
 * Empty weight: 14450 lbs
 * MTOW: 23600 lbs
 * Powerplant: 2x Napier Gazelle 501 turboshafts (1650 hp each)
 * Max speed: 160 mph
 * Cruise speed: 145 mph
 * Range: 500 mi
 * Service ceiling: 15000 ft
 * Armament: 4 torpedoes or 4 depth charges or 4 AS.12 anti-ship missiles; 30 sonobuoys

Yarrows Yarksis HC.2, AHC.2, HSR.2, HASR.2
An upgraded version of the Yarksis entered production in late 1978. The most noticeable external difference, aside from the 7' 8" increase in length, was the redesigned aft pylon, which was widened at the base to house two engines. Instead of the two Napier Gazelles, the new version was powered by three Turbomeca Makila 1A1 turboshafts, each producing 1742 hp, giving a very significant increase in power over the original Yarksis.

The first twelve units, built from November 1978 to March 1979, going to the BC Army, where they were designated Yarksis AHC.2 (serials AA9-101 to AA9-112; these included some Army-specific features, much like the previous AHC.1). Deliveries of the transport version to the RBCAF, as Yarksis HC.2 (serials BC14309 to BC14318), began in February 1979, with a total of ten being delivered during that year. The new transport version was fairly successful in export sales as well, with a grand total of 217 being built between 1979 and 1988 for the Indian Air Force (40), Royal Australian Air Force (26) and Australian Army (20), the Royal Rhodesian Air Force (12), the Republic of China Air Force (12), the Philippine Air Force (10), the Canadian Armed Forces (8), and 89 to civilian operators around the world.

A search-and-rescue variant was also built, also entering production in 1979. Twelve were delivered to the RBCAF as Yarksis HSR.2 (serials BC13313 to BC13324) and ten to the RBCN as Yarksis HASR.2 (serials NH3311 to NH3320), along with ten to the BC Coast Guard. 109 were exported - 8 to the Icelandic Coast Guard, 15 to the Royal Australian Air Force, 6 to the Royal New Zealand Air Force, 8 to the Canadian Armed Forces, 6 to the Canadian Coast Guard, 6 to the Royal Rhodesian Air Force, 6 to the Royal Hong Kong Air Force, 30 to the Indian Air Force and 24 to the Indian Navy.

Specifications

 * Crew: 3 (4 for SAR versions)
 * Capacity: 24 fully-equipped troops or 30 passengers or cargo or 16 stretchers plus 2 seats plus 2 attendant
 * Length: 62 ft 0 in
 * Empty weight: 25400 lbs
 * MTOW: 53000 lbs
 * Powerplant: 3x Turbomeca Makila 1A1 turboshafts (1742 hp each)
 * Max speed: 170 mph
 * Cruise speed: 155 mph
 * Range: 520 mi
 * Service ceiling: 19000 ft

Yarrows Yarksis HS.2
In 1975, six years after the anti-submarine Yarksis HS.1 entered service with the Fleet Air Arm, the RBCN issued a requirement for an upgraded version.

Part of the new requirement was to feature as much BC-made content as possible. To this end, the Sensors Division of the BC Telephone Company obtained a licence to manufacture the Plessey Type 195 dipping sonar used on the HS.1. With assistance from Plessey's and a Canadian manufacturer of sonobuoys the design was modernised, with the first tests being undertaken in 1978 with the sonar mounted on a modified Yarrows Yoho HS.1. A licence was also obtained by BCT-Sensors to manufacture the British Sea Spray radar for use in the HS.2. Further, a magnetic anomaly detector was added in a belly radome. Like the HS.1, four torpedoes or depth charges could be carried, or four Sea Skua anti-ship missiles, which were introduced to BC service with the HS.2.

The new design retained the dimensions of the HS.1, but added the modified aft pylon of the HASR.1, as it incorporated the three Makila 1A1 engines of the Yarksis 2.

24 Yarksis HS.2 (serials NH6325 to NH6348) were delivered to the RBCN between August 1980 and January 1982; from 2000, twelve were upgraded to HS.2A standard (q.v.). The type also saw limited export, with 14 going to the Mexican Navy in 1981-82 and 10 to the Royal Hong Kong Navy in 1982-83.

Specifications

 * Crew: 5
 * Length: 46 ft 5 in
 * Empty weight: 15200 lbs
 * MTOW: 26200 lbs
 * Powerplant: 3x Turbomeca Makila 1A1 turboshafts (1742 hp each)
 * Max speed: 160 mph
 * Cruise speed: 145 mph
 * Range: 510 mi
 * Service ceiling: 19000 ft
 * Armament: 4 torpedoes or 4 depth charges or 4 Sea Skua anti-ship missiles; 30 sonobuoys

Yarrows Yarksis HC.2A, AHC.2A, HSR.2A
The existing Army and Air Force HC.2, AHC.2 and HSR.2 helicopters were modernised by Supermarine BC in 2000-2002 with a complete airframe overhaul, an all-new glass cockpit, new avionics, instrumentations and other systems, and new, more powerful engines - the original Turbomeca Makila 1A1 were replaced by the Makila 2A, each producing 2415 hp.

Eight RBCAF HC.2 were upgraded to Yarksis HC.2A standard (serials BC14319 to BC14326), ten RBCAF HSR.2 were upgraded to Yarksis HSR.2A standard (serials BC13325 to BC13334), and eight BC Army AHC.2 were modernised to Yarksis AHC.2A standard (serials AA9-201 to AA9-208).

The upgrade program has been on offer to all Yarksis 2 owners since 2001, and along with several civilian operators, the Royal Rhodesian Air Force, the Royal Hong Kong Air Force, the Icelandic Coast Guard and the Canadian Coast Guard have opted to undertake the upgrade.

Specifications

 * Crew: 3 (4 for SAR versions)
 * Capacity: 24 fully-equipped troops or 30 passengers or cargo or 16 stretchers plus 2 seats plus 2 attendant
 * Length: 62 ft 0 in
 * Empty weight: 26300 lbs
 * MTOW: 55200 lbs
 * Powerplant: 3x Turbomeca Makila 2A turboshafts (2415 hp each)
 * Max speed: 170 mph
 * Cruise speed: 155 mph
 * Range: 520 mi
 * Service ceiling: 19000 ft

Specifications

 * Crew: 5
 * Length: 46 ft 5 in
 * Empty weight: 15200 lbs
 * MTOW: 26200 lbs
 * Powerplant: 3x Turbomeca Makila 1A1 turboshafts (1742 hp each)
 * Max speed: 160 mph
 * Cruise speed: 145 mph
 * Range: 510 mi
 * Service ceiling: 19000 ft
 * Armament: 4 torpedoes or 4 depth charges or 4 AS.12 anti-ship missiles; 30 sonobuoys